The present invention relates generally to the golf clubs and, more particularly, to golf club heads.
Modern golf clubs have typically been classified as either woods, irons or putters. The term “wood” is a historical term that is still commonly used, even for golf clubs that are constructed of steel, titanium, fiberglass or other more exotic materials, to name a few. The term “iron” is also a historical term that is still commonly used, even though those clubs are not typically constructed of iron, but are rather constructed of many of the same materials used to construct “woods”.
Many advancements have been achieved, particularly over the past couple of decades, to make it easier to hit longer and straighter shots with woods and irons. In general, golf clubs are now designed to be more forgiving, so that shots that are struck less than perfectly will still have fairly consistent distance and directional control. Moreover, club heads now commonly are constructed of combinations of materials, to attempt to optimize the ball flight desired by a particular type of player.
One particular improvement that relates to irons is the use of perimeter weighting, whereby a disproportionate amount of the total weight of a club head is positioned behind and proximate the perimeter of the club head's striking face, thereby creating a cavity immediately behind the striking face. The cavity is formed by the club face wall and the weight that is placed around and behind the club face. This type of club is typically referred to as a “cavity back” iron. By moving the weight peripherally away from the center of gravity (CG) of the club head, the club is made to be more forgiving on off-center hits, resulting in more consistent distance and directional control. Further, perimeter weighting generally increases the moment of inertia about the club's CG, resulting in less twisting due to off-center hits, and more accurate shots.
There are so-called “hollow” irons that incorporate a rear wall that is spaced from the front striking face. This also increases the moment of inertia about the club's CG and is found to benefit some higher handicap golfers. Some hollow irons more closely resemble fairway woods in cross-sectional shape, while other hollow irons may resemble cavity back irons in their cross-section.
Another improvement is the use of lighter and stronger materials, which enables club designers to move the CG to an optimal location on a wood or iron. Such a movement can make the club either easier to hook or to fade, if the movement is made either closer to or farther from the hosel. Similarly, if the CG is moved higher or lower with respect to the club face, the golf ball launch conditions can be altered. For instance, lowering the CG generally makes it easier to get the ball airborne for either an iron or a wood. Conversely, raising the CG promotes a more boring ball flight that generally leaves the club face at a lower launch angle.
Generally, it has been shown that it can be advantageous for players with higher handicaps to use clubs with a lower CG. This is especially true for long irons, such as for example a 3-iron. Club designers have responded to this prospective advantage by lowering the CG of both woods and irons for clubs intended for higher handicap players. The most common way that this has been accomplished for irons is to move as much weight as possible to the area proximate the sole of the club. This results in a concentration of weight proximate the sole. Often, for these types of irons, the transition from the cavity to the weight on the sole is abrupt, compared to traditional irons having a smoother transition. When viewing a cross-section of the lower portion of the club face, a dramatic change in the thickness of the face nearer the sole often is apparent in such sole-weighted club heads.
While it is recognized that the lower CG of the improved clubs can be beneficial, such a lowering can have negative side effects. First, the concentrated mass proximate the sole can increase the stiffness of the club head. This can cause a noticeable change in the club's feel. Feel is a term that is generally used by skilled practitioners to denote a subjective expression of the way a club feels to one's hands when striking a golf ball, or the way it sounds. Feel is generally perceived as audible to tactile feedback to the golfer. Different sensations due to striking the ball in different locations on the club face may make a club less desirable to a potential user.
Second, the weight concentration proximate the sole can lead to different levels of flex at different points on the club face. The area of the face proximate the thickest portion of the sole is likely to flex less than the area proximate the inner areas of the striking face. Such a change in flex can adversely affect performance.
Third, the weight concentration can lead to excess vibration, which can adversely affect the feel of the golf club, including the sound made by the club.
It should be appreciated from the foregoing description that there is a need for an improved golf club head that creates a more consistent flex when striking the ball, improves the club's feel, and reduces vibration. The present invention satisfies this need and provides further related advantages.